The High Occupancy Toll (HOT) lanes on the Harbor Freeway in Los Angeles. / By Robert Hanashiro, USA TODAY

by Larry Copeland, USA TODAY

by Larry Copeland, USA TODAY

Jessica Frend, government affairs adviser for a downtown Washington, D.C., law firm, was doing some holiday shopping last week at Tysons Corner, an upscale retail center in Northern Virginia.

As she was leaving the mall with her infant son to drive back to her home in Bethesda, Md., he started letting her know he was hungry. "I knew he would be needing to be fed pretty quickly," says Frend, 29. "I used my E-ZPass (transponder) and hopped on the 495 Express Lanes."

By using the new, real-time toll lanes, which opened Nov. 17, Frend figures she shaved about half the time off her trip - at a cost of 45 cents - and was able to feed her son before he got irritable.

That kind of reliable trip on highways that are continually growing more congested is one of the strongest selling points of the highway projects that some transportation specialists say are the future of urban tolling in the USA. These are lanes on highways, alongside free lanes, where people pay a fluctuating toll that rises as more drivers use the lanes and drops as demand falls off. Carpoolers, motorcyclists and bus passengers ride for free on most of them.

If a trip takes 20 minutes one day, 45 minutes the next, and 35 minutes the following day - because of varying road conditions and congestion - motorists must set aside 45 minutes for that trip each day to ensure that they're on time.

"The product we're selling Northern Virginia commuters is a faster and more reliable commute," says Jennifer Aument, vice president of corporate relations in North America for Transurban, one of two private firms that partnered with the Virginia Department of Transportation on the project along Interstate 495, known as the Capital Beltway. "It's not just about going faster, but it's also the reliability."

Aument says her firm, which manages the toll lanes, is contractually obligated to keep traffic moving at 45 mph. But "customers can expect to travel about 55 mph even during rush hour." Traffic sensors on poles along the road measure traffic conditions, including speed.

Another feature of this type of tolling: It helps ease congestion by attracting more commuters onto buses, where they know they can expect a reliable trip time, says Jim Ely, vice president of toll services for HNTB Corp., a national infrastructure firm.

In South Florida, where such toll lanes opened on Interstate 95 in 2010, bus ridership "has been wildly successful," says Jeff Weidner of the Florida Department of Transportation. "We have more than 5,000 rides a day, which is more than 2,500 people. That's 2,500 vehicles out of the traffic during the peak periods. And most of these are choice riders - 77% of them have access to a car."

The Northern Virginia toll lanes are a $1.9-billion, public-private venture featuring 14 miles of four "dynamic pricing" lanes on I-495.

Another new real-time tolling project opened Nov. 10 in Los Angeles County. L.A.'s first toll road is two lanes in each direction on an 11-mile stretch of Interstate 110, the Harbor Freeway. It's a one-year demonstration project sponsored by a $210-million federal grant, says Rick Jager, spokesman for the Los Angeles County Metropolitan Transportation Authority, known as Metro.

"So far, so good," Jager says. "When we opened, we had 30,000 (toll lane) transponders. Since then, that has grown to over 60,000." Metro allows carpools of two or more people, motorcycles and buses to use the lanes for free. Others pay a toll of 25 cents to $1.40 per mile. When speeds drop below 45 mph, the lanes are closed to solo drivers, Jager says.

Even some frequent critics of tolling on interstates like the fluctuating tolling. "It gives drivers another option," says Greg Cohen, president of the American Highway Users Alliance. "It's only feasible in very congested areas."

Bill Carbaugh, senior vice president of Guardian Realty in Bethesda, used the 495 Express lanes recently to get from a morning meeting in Tysons Corner, Va., back to his office.

"I'd use it for both work and personal trips," says Carbaugh, 48. "if I'm trying to get to the courthouse or a meeting, or if I'm trying to get to my son's basketball game or my daughter's basketball game. Normally, if I leave at 5, I would think I can get there in an hour. But with the traffic here, that's not enough sometimes. I would be willing to pay the toll to get there on time."